MARIANNA, Fla. — University of South Florida researchers began exhuming dozens of graves Saturday at a former Panhandle reform school where horrific beatings have been reported in hopes of identifying the boys and learning how they died.

The digging and work at the site of the former Dozier Boys School will continue until Tuesday, with researchers hoping to unearth the remains of four to six boys before resuming at a later date, said Erin Kimmerle, the USF anthropologist leading the excavation.

After work began Saturday, relatives of one of the boys believed to be buried at the school held a private prayer at the grave sites. The family has provided DNA in hopes of finding a match with Robert Stephens. School records show he was fatally stabbed by another inmate in 1937, but his family hopes to confirm how he actually died through the exhumation efforts.

If his remains are found, his family says they will be reburied in a family plot in Quincy.

"That will be a great sense of homecoming," Tananarive Due said. The boy was Due's great-uncle. She was at the site Saturday with her son, father and husband, and said she hopes that other families will also be able to locate relatives buried there.

"Their families never had a proper opportunity to say goodbye to their loved ones. In a lot of cases children just disappeared," said Due, who lives in Atlanta.

Former inmates at the reform school from the 1950s and 1960s have detailed horrific beatings in a small, white concrete block building at the facility. A group of survivors call themselves the "White House Boys" and five years ago called for an investigation into the graves. In 2010, the Florida Department of Law Enforcement ended an investigation and said it could not substantiate or refute claims that boys died at the hands of staff.

USF later began its own research and discovered even more graves than the state department had identified. USF has worked for months to secure a permit to exhume the remains, finally receiving permission from Gov. Rick Scott and the state Cabinet after being rejected by Secretary of State Ken Detzner, who reports to Scott.

"In these historic cases, it's really about having an accurate record and finding out what happened and knowing the truth about what happened," Kimmerle said of efforts at the school, which opened in 1900 and shut down two years ago for budgetary reasons.

Kimmerle said the remains of about 50 people are in the graves. Some are marked with a plain, white steel cross, and others have no markings.

Robert Straley, a spokesman for the White House Boys, said the school segregated white and black inmates and that the remains are located where black inmates were held. He suspects there is another white cemetery that hasn't been discovered.

"I think that there are at least 100 more bodies up there," he said. "At some point they are going to find more bodies, I'm dead certain of that. There has to be a white graveyard on the white side."

Among those that have pushed to allow USF to conduct the research are Florida's Republican Attorney General Pam Bondi and Democratic U.S. Sen. Bill Nelson.

"My goal all along has been to help bring closure to the families who lost loved ones at Dozier. I feel great relief that the work to identify human remains is now underway," Bondi said through a spokeswoman.

The holiday weekend's initial work is meant to ensure that the process works smoothly before researchers return to the site. The remains will be brought to Tampa to be studied. DNA obtained will be sent to the University of North Texas Center for Human Identification for analysis. The hope is that it can be matched to relatives. Ten families have contacted researchers in hopes of identifying relatives that might be buried at Dozier.